KC&C Says Colo. Wildfire Caused $1 Billion in Insured Losses

The wildfire that ignited on Dec. 30 in Boulder County, Colorado destroyed 1,000 structures and caused insured losses of about $1 billion, catastrophe modeler Karen Clark & Co. said Wednesday.

The blaze, called the Marshall Fire because it it started off of Marshall Road, was contained after the area received about 10 inches of snow on Dec. 31. But by that time the inferno had become the most destructive wildfire in Colorado history, KC&C said.

The previous record belonged the East Troublesome Fire of October 2020, which destroyed over 500 structures and cost nearly $500 million in insured losses.

KC&C said Colorado has experienced seven major loss producing fires since 2010. Other notable destructive fires include the Waldo Canyon Fire in 2012, which resulted in around $450 million in insured losses, and the Black Forest Fire of 2013, which resulted in nearly $400 million in insured losses.

“Months of unusually warm and dry weather along the Colorado Front Range primed the environment for the fast-spreading Marshall Fire,” KC&C said. “Precipitation had been at record lows in the region since July, and Denver had just experienced its second warmest fall season on record. The unseasonably hot and dry weather led to desiccated vegetation throughout the state, which can easily ignite and spread fire.”

The exact cause of the Marshall Fire is still under investigation, but KC&C said an intense, downslope wind event that impacted the Colorado Front Range assisted the fast rate of spread. On the morning of Dec. 30, strong winds were flowing nearly due east across the high peaks of the Colorado Rockies in the mid-levels of the atmosphere. By midday, an amplified mountain wave had developed over the Front Range and began to bring those strong mid-level winds to the surface, where gusts of over 100 mph were reported.

Downslope wind events of that magnitude are uncommon, but not unprecedented, in Colorado. In fact, a 110 mph wind gust had been recorded in Boulder County during another downslope wind event less than a week before the Marshall Fire, KC&C said. As is typical of downslope winds, the air flowing into Boulder County from the mountains during this event was hot and dry, enhancing the potential for rapid fire spread.

The wildfire season does not typically extend into the winter in Colorado because of the usual snow cover and cold temperatures. But KC&C said the Marshall Fire is part of a general trend of a lengthening fire season and drier fuels in the Western United States due to global warming.

The Marshall fire burned approximately 6,000 acres and devastated entire subdivisions throughout Superior, Louisville, and unincorporated Boulder County, Colorado, the catastrophe modeler said.

Here’s a breakdown of the destruction, according to the Boulder County Sheriff’s Office:

• Louisville: 553 destroyed, 45 damaged.
• Superior: 332 destroyed, 60 damaged.
• Unincorporated Boulder County: 106 destroyed, 22 damaged.

In Louisville, a suburban area about 20 miles northwest of Denver, hundreds of homes and a large commercial area, including a shopping center and a hotel, were among the destroyed structures.

Source: Karen Clark & Co.

About the photo: Ron Damario peers into what remains of his charred safe, Monday, Jan. 3, 2022, in Louisville, Colo. Damario lost his home after a fire ripped through Boulder County on Thursday. (AP Photo/Brittany Peterson)